Serological and Molecular Investigation on Toxoplasma gondii Infection in Wild Birds

Abstract

Toxoplasma gondii is an obligate apicomplexan zoonotic parasite that infects humans and other animals and is responsible for toxoplasmosis. This parasite causes one of the most common parasitic infections in humans worldwide. Toxoplasmosis meets the requirements for a One Health Disease due to its ability to affect the health of human beings as well as domestic and free ranging animals. Integrating human, domestic animal, and wildlife data could better assess the risk and devise methods of control. A first step of such an approach would be the knowledge of the prevalence of parasitosis in humans and animals in selected areas. Therefore, the aim of the present study was to evaluate the occurrence of Toxoplasma infection in 216 free ranging birds belonging to different genera/species by serology and molecular techniques. Twenty-five out of 216 animals (11.6%) were positive to the immunofluorescence antibody test (IFAT) with antibody titers ranging from 1/20 to 1/320, and 19 of them (8.8%) also showed a positive PCR for Toxoplasma DNA. The results confirmed the widespread occurrence of Toxoplasma infection in wild birds and serological data were corroborated by molecular results in birds that also had low antibody titers. The knowledge of the wide occurrence of the parasite in game and wild birds should enhance the accurate estimation of the risks in handling, managing, and eating these species with regard to domestic carnivores as well as the impact of viscera and offal in the environment.

Molecular Survey on Toxoplasma gondii and Neospora caninum Infection in Wild Birds of Prey Admitted to Recovery Centers in Northern Italy

“…A mismatch between the serological result reported by these two studies and the data obtained from the present molecular epidemiology study is therefore highlighted. In wild birds of prey, however, seroprevalence does not always correspond to positivity to the PCR on the brain [ 10 ], demonstrating that the association between seropositivity and the presence of T. gondii DNA in the tissues of these species is yet to be investigated. As evidence of the possible lifelong non-persistence of immunity, in the present study, no difference in the prevalence values was recorded between young and adult animals, as already reported in other wild species [ 27 ].…”

“…Darwich et al [ 9 ], by means of a nested PCR targeting the 529 bp repetitive fragment, found T. gondii DNA in the brain of only two positive raptors among the 136 examined in Spain. Nardoni et al [ 10 ], using a nested PCR targeting the B1 gene, found T. gondii DNA in the brain and heart samples belonging to two positive Falco tinnunculus , among 15 raptors examined in Central Italy. A higher prevalence value was recorded by a recent study conducted in Turkey: T. gondii DNA was detected by Real Time PCR targeting the 529 bp repetitive fragment in the brain and heart samples of 92.3% out of 43 examined raptors [ 28 ].…”

“…In raptors, various seroepidemiological and molecular studies reported T. gondii infection with different prevalence values, depending on the host species, the geographical area of origin, and the diagnostic technique used [ 6 , 7 , 8 , 9 , 10 ]. Raptors are considered resistant to clinical infection.…”

Epidemiologic Survey on Toxoplasma gondii and Trichinella pseudospiralis Infection in Corvids from Central Italy

“…In a previous investigation, the use of both heart and brain tissues was proven to enhance the sensitivity of testing for T. gondii DNA [11]. Therefore, although heart tissue is considered a more sensitive tissue in respect to brain tissue in chickens [5,7,11,40,41], the PCR prevalence rates recovered in the present study are probably underestimated, because only cardiac samples could be examined.…”

“…T. gondii has a cosmopolitan distribution and represents one of the most common human parasites [4,5]. In previous studies performed by molecular and/or serological analysis, different avian species have been found to be infected by T. gondii worldwide [6][7][8][9][10][11], with high prevalence values often observed in raptors and scavenger birds [1,7,[12][13][14][15][16][17]. Nevertheless, to the best of our knowledge, data about T. gondii infections in corvids from European countries are scarce, being referred to in only two studies carried out in Spain [6,18].…”